Facile Oxyselenation of Olefins in the Presence of Copper(II) or Copper(I) Chloride as Catalyst

Article abstract of DOI:10.1021/jo01298a039

Treatment of olefinic hydrocarbons with phenyl selenocyanate in alcohol in the presence of copper(II) or copper(I) chloride affords β-alkoxyalkyl phenyl selenide in good yield.Similar reactions in aqueous tetrahydrofuran or acetic acid-chloroform give the corresponding selenide.The reaction is trans stereospecific in the cases of trans-2-butene, cis-2-butene, and cyclohexene and regiospecific in the cases of styrene, acrylaldehyde, crotonaldehyde, and vinylacetate, respectively.The reaction proceeds even with a catalytic amount of copper(II) chloride.Of the various transition-metal salts examined, nickel(II) halides are similar to copper(II) or copper(I) halides as catalyst; the chlorides of Cr(III) and Co(II) are moderately effective, while the chlorides of Mn(II), Fe(III), Fe(II), Zn(II), Ag(I), Cd(II), Hg(II), Hg(I), Tl(III), and Tl(I) are almost ineffective.The use of the pyridine complex of copper or nickel halides suppresses the reaction.The reaction is presumed to proceed via (i) the polarization of the Se-CN bond by coordination of the effective metal salt to the cyano group and (ii) a nucleophilic attack of olefin on the polarized selenium.The substituent parameters of phenylseleno and selenocyanato groups for 13C NMR have been found to be +13 and +15 to <*>16 ppm for the α carbon and +6 and +6 to <*>7 ppm for the β carbon, respectively.